Solid-state synthesized Li4Ti5O12 for ultrafast lithium ion storage enabled by carbon-coating induced particle size tailoring

We synthesize the size-tailored Ce:Li 4 Ti 5 O 12 via a facile solid-state method. During the synthesis, a carbon-coating forms in-situ on the Ce:Li 4 Ti 5 O 12 particles to limit their grain growth. The coating is later removed to facilitate the Li + diffusion during charge/discharge. The composition, structure, and morphology of the obtained samples are characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma elemental analysis , thermal gravimetric analysis , scanning electron microscopy, and transmission electron microscopy . The results confirm the particle-size tailoring effect induced by the carbon-coating. The size-tailored Ce:Li 4 Ti 5 O 12 electrode demonstrates high reversible capacity of 164, 161, 158, 149, 136, and 116 mAh g −1 at 0.5C, 1C, 2C, 5C, 10C, and 20C, respectively, which are significantly improved from the pristine Li 4 Ti 5 O 12 . Moreover, it is also capable of maintaining 96% and 92% of the initial capacity at the high rate of 10C and 20C after 1000 cycles, exhibiting excellent cycling stability. Finally, we fabricate a full cell with LiFePO 4 cathode, which delivers reversible capacity of 110 mAh g −1 at 5C with little capacity fading after 1200 cycles, confirming the outstanding electrochemical performance of size-tailored Ce:Li 4 Ti 5 O 12 anode.